Check-valve unit for hydraulic jacks



Dec. 14 1926. 1,610,499-- J. G. DYBENs cHEqK VALVE UNIT FOR HYDRAULIC JAoKs Filed Deo. 22. 192.4

' Irre/tru?.

Patented Dec. 14, 1926.

UNITED STATES JOHN G. DYBENS, OF LOS ANGELES, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO HERMAN D. EBERLE.

CHECK-VALVE UNIT FOB HYDRAULIC JACKS.

Application led December 22, 1924. Serial No. 757,362.

My invention has to do with hydraulic jacks, and particularly with improvements which increase the commercial value of a jack of this character.

Hydraulic jacks broadly comprise a reservoir chamber in which a non-compressible fluid such as oil is stored; a cylinder in which a piston is movable; a pump construction which is arranged to take oil from the reservoir and pump it into the cylinder below the piston` thus pressurally raising the piston in the cylinder; and a by-pass for allowing the oil in the cylinder to return to the reservoir, thus lowering the piston in the cylinder. A passage connecting between the oil reservoir and the pump vhas a check valve for preventing a reverse flow through this passage, that is, a flow of oil from the pump to vthe reservoir. A passage from the pump to the cylinder is provided with a check valve to prevent a reverse l'low therethrough, that is, a ilow of oil from the cylinder to the pump. These check valves are provided directly in a casting of the hydraulic jack, thus requiring considerable small machine work thereon. This tends to increase the cost of the jack and places the check valves in inaccessible positions sothat the jack must be entirely disassembled to get at these valves.

lt is an object of my invention to provide a hydraulic jack which has certain `novel features of construction which render it simple in construction, reliable in performance yand economical to produce.

lt is another object of my invention to provide a hydraulic jack having a novel form of check valve unit employed therein.

A. jack designedafter my invention broadly comprises a reservoir chamber, a cylinder having a piston movably disposed therein, and a pump for pumping oil from the reservoir into the cylinder. In a base oE the jack I provide a cavityin which I place the novel check valve unit of my invention. This check valve unit has an inlet passage which connects between an intake passage extending from the reservoir chamber Vand the barrel of the pump, and has an outlet passage which connects between the barrel of thepump and an exhaust passage connecting `with the cylinder of the jack.v I screw the `barrel of the pump into the upper end of the ycavity so that the lower end thereof engages the check valve unit and retains it securely in place. The check valve' unit is situated Fil-:ISSUED in such a position that it is conveniently accessible and may be readily removedl for inspection or repain The check valve unit is of such a character that it may be .very cheaply produced, owing to its size and the ease with which it may be handled for machining and assembling. By using a" unit of this character, I eliminate much machine work on the base casting ofthe jack and in this manner I reduce the cost of the jack.

Other objects and advantages of the in vention will be made evident hereinafter.

Referring to the drawings which are for illustrative purposes only,

Fig. 1 is a sectional view taken through 7 a hydraulic jack employing the features of vmy invention.

Fig. 2 is yan enlarged cross sectional view through a check valve unit having the features of my invention.

"Fig, 3 is a plan view of the unitshown in Fig. 2; l l

Fig." 4 is an enlarged detail of a ball re-y tainer `used in the check valve unit construction.

Inthe form of my invention shown in the drawings, 11 represents a hydraulic jack' having a base casting 12 and a head casting 13. The 'base casting 12 is provided with a central cavity 14 into which the lower end 35 15 of an inner cylinder wall 16 providing a cylinder chamber 17 is screwed. A piston 18 is movably arranged in the cylinder chamber 17 having a stem.188L extending upward ltherefrom through a stulling box 19 of 90 the head casting 13. An outer reservoir wall 20 is connected with the cylinder wall 16 by a top 22, this reservoir wall 20 providing a reservoir chamber 23.- The lower face/24 of the reservoir -wall 2O is beveled 05 as shown, and engages with a beveled annular face 25 of the base casting 12, providingl l a lluidtight-joint between the base casting 12 and the head casting 13.

To one side of the base casting 12 as clear- 100 'ly shown in Fig. 1,.is acylindrical cavity in which a check valve unit 31 having the features of my invention isinstalled. 'The lower'portion of the cavity 30 provides a 'l5 check valve conicalseat 32 and the lower beveled end 105.

33 of the body 34 of the check valve unit 31 engages this conical seat 32. The upper part of the cavity 30 is threaded at 35, and

a pum barrel 36 is screwed thereinto. The lower ace 37 'of the pump barrel 36 engages 110 with the upper fac/e 3S'of the body 34, clamping the body securely against the conical seat 32, thus securing the check valve unit in place. A pump plunger is reciprocable in the barrel 36, this plunger being reciprocated by mechanism not shown in the drawings. Adjacent to the lower portion ot the cylindrical cavity 3() is an annular channel 42. An intake passage 43 is provided in the base casting 12, which intake passage 43 extends from the oil reservoir chamber 23 to the annular channel 42. An exhaust passage is provided in the base casting 12, this exhaust passage 45 extending from the lower end of the cavity 30 to the lower portion of the cylinder chamber 17 as shown in Fi 1 of the drawings.

s clearly shown in Figs. 2 to 4, inclusive, the check valve unit has an inlet passage ,50 which extends from the lower portion of the cylindrical face of the body 34 to the upper face 38 theerof. yThe portion 51 of the lnlet passage connects with the cylindrical face of the body 34 at such a place that it is in communication with 'the annular channel 42. The upper portion of the inlet pasage- 50 is enlarged so as to provide a ball chamber 52 and a seat 53. In the ball chamber 52 is a valve ball 55 which is arranged for engagement with the seat 53. The ball 55 is retained in the chamber-52 by means of a ball retainer 57 which is clearly shown in Fig. 4. This ball retainer 57 has an annular portion 58 and a radially extending leg 59. An annular recess 61 is provided in the upper end of the wall of the chamber 52 and in this recess 61 is placed the annular portion 58 of the retainer 57 so that the leo' 59.extends.toward the center of the cham-ber 52, thus preventing the ball cent to the inlet passage .50 is an outlet passage 64 which extends substantially axially through the body 34, as shown. The lower portion of the outlet passage 64 is enlarged at the lower end so as to provide a ball chamber 65 and a ball seat 66. In the chamend of the-wall of the ball chamber 65 in' which a ball retainer identical with the ball retainer 57 is retained. The upper end of the outlet assa 64 is enlarged and threaded as in icate at 72 in the drawings.

Again referring to Fig. 1, it is evident that the inlet passage 50 of the check valve unit 31 communicates between the annular` channel 42 and the barrel 36, and that the outlet passage 64 connects between the barrel 36 and the exhaust passage 45. The valve ball 55 permits a flow of ud from the annular channel 42 into the barrel-36 but prevents reverse flow, that is, a flow from the barrel 36 to the annular channel .reservoir 23 through the intake passage 43 into the annular channel 42. The oil passes through the inlet 50. raisinsT lhc ball 55 from its Seat and into the space in the barrel 36 below the plunger 40. lVhcn the plunger is moved downward in the barrel 36, the ball 55 closesthe inlet 50 so as to prevent Va flow of oil from the barrel 36 through the inlet 50. and the oil will flow through the outlet 64 removing the ball 67 from its seat and will flow through the exhaust passage 45 into that portion of the cylinder chamber 17 below the piston 18. In this manner oil is pumped from th-e reservoir 23 into the cylinder chamber 17 below the piston 18, thus forcing the piston upward in the chamber 17. During the upward stroke of the plunger 40, the valve ball 67 closes the-inlet 64 and prevents a reverse flow of oil from the chamber 17, and during the downward stroke of the plunger 40, the valve ball 55 closes and prevents a reverse flow into the oil reservoir 23. A by-pass 7 5 is provided in the base casting 12 which connects between the lower end of the cylinder' chamber 17 and the oil reservoir 23` as shown in Fig. 1. This by-pass 7 5 is ordinarily closed by a valve 76 and when it is desired to lower the plunger 18, this by-pass is opened by unseating the valve 76 as is obvious, thus allowing the oil in the cylinder chamber 17 to flow through the by-pass 75 and into the oil reservoir 23.

From the drawings and the foregoing dcscription, the pronounced advantages of my invention are very evident. The machine work required on the base or head castings is reduced to a minimum bv the elimination of the necessity for providing check valve arrangements therein. The performance of small machine 'work in inconvenent positions on large castings is a rather laborious task, and tends to increase the cost of such castings. By the employment of a check valve unit of my invention I am able to do all small machine Work on the body 34, this body 34 being very convenient to handle. and may be turned out very cheaply. The. check valve unit 34 isconveniently retained in place by the pump plunger 36 and. therefore, no, extra retaining parts are required. The check valve unit is placed in such a position that it is accessible, and may readily be removed for inspection or repairs. By providing the annular channel 42. it is not necessary to align the portion 51 of the lun inlet passage 50 of the unit 31 in any parthe check valve unit- 31. The threaded poi'- tion 72 of the passage 64 is arranged to receive the threaded end of a removing member, thus facilitating the removing of the unit 31 from the cavity 30.

I claim as my invention:

1. In a hydraulic jack, the coinbinat'on,

of a head casting having a reservoir chamber and a cylinder; a base to which said head is secured, said base having a cavity. an intake passage connecting between said reservoir chamber and said cavity, and an exhaust passage connecting between said cylinder and said cavity; .a pump barrel securedin said cavity; a plunger reciprocally disposed ifn said barrel; and a check valve unit lin said cavity,.said unit having an inlet passage connecting said intake pas'"age with said barrel and an outlet passage connecting said exhaustpassage and said barrel.

2. In a hydraulic jack, the combination of: a head casting having a reservoir chainber and a cylinder; a base to which said head issecured, said baseA haying a cavity,

an intake passage connecting between said' reservoir chamber and said cavity, and an exhaust passage connecting between said cylinder and said cavity; a pump barrel secured in said cavity; a plunger reciprocally disposed in said barrel; and a cheek valve unit secured in saidcavity by said barrel, said unit having an inlet passage connecting said intake passage with said barrel and an outlet passage connecting said exhaust passage and said barrel.

3. A hydraulic jack as defined in claim 2 in which said cavity has a seat and said unit is retained against said seat by said barrel.

4. In a hydraulicj ack, the combination of:

a head casting having a reservoir chamber and a cylinder; a base to which said head is secured, saidbase having a cavity, an annular channel formed in the wall of said cavity, an intake passage connecting said reservoir to said annular channed, and an exhaustpassage connecting between the vbottom of said cavity and said cylinder; a pump barrel screwed into the upper part of said cavity; a pump plunger arranged in said barrel;

and a check valve unit disposed in said cav--` ity, said unit being engaged by the lower end of said barrel and being thereby retained in place, said unit-'having aninlet passage connecting between said annular channel and said barrel, a check valve in said passage allowing a How` of fiuidfrom Vsaid annular channel into said barrel but preventing a flow from' said barrel into said annular cha-npassage extending from the side of said body to yone end thereof and said outlet passage extending from one end to the opposite end of said body; and check valves for preventing reverse flows through said inlet and outlet passages.

6. In a check valve unit, the combination ofzfa cylindrical body, said body comprising an inlet passage extending from the side to one end of said body, a valve seat formed in said inlet passage, an outlet passage extending from one end to the opposite end of' said body, and a valve seat formed in said outlet passage; a ball adapted to engage said seat in said inlet passage; a second ball adapted to engage said seat in said outlet passage; a ball retainer arranged in said inlet passage for retaining said ball in place; and a second ball retainer arranged in said outlet passage for retaining said second ball in lace.

7. In a ydraulic jack, the combination of: a base; a piston cylinder provided'upon said base; a piston slidably disposed in `said cylinder; means for forming a reservoir upon said jack, there being formed in said base a cavity, an inta-ke passage communicatin between said cavity and said reservoir, an an exhaust passage communicatingbetween said cavity and said cylinder; a check valve unit disposed within said cavity; and a fluid forcing means secured upon said base so as to hold said unit in said cavity and 'said base; a piston slidably disposed in said cylinder; means for forming a reservoir upon said jack, there being formed in said base a cavity, an intake passage communicating between said cavity and said reservoir, and an exhaust passage communicating between said cavity and said cylinder; a check valve unit disposed within said cavity; and a fluid forcing means secured upon said base so as to hold said unit in said cavity and coinmunicate throughsaid unit with said inlet and exhaust passages, said check valve unit having a face which forms a iuid tight engafgement with a surface of said cavity and a ace which forms a iiuid tight engagement with said fluid forcing means. `i

9. In a hydraulic jack, the combination of: a base; a piston cylinder provided upon said base; a piston slidably disposed in said cylinder; means for forming a reservoir upon said jack, there being formed in said base a `cavity, an intake passage communicating between said cavity and said reservoir, and an exhaust passage communicating between said cavity and said cylinder; a check valve unit disposed within said cavity; and a fluid forcing means secured upon said base So as to hold said unit in said cavity and communicate through said unit with said inlet and exhaust passages, said check valve unit having a face which forms a fluid tight engagement with a surface of said cavity and a face which forms a fluid tight engagement with said fiuid forcing means, said engagementsbeing maintained by pressure of said iuid forcing means against said check valve unit. Y

10. In a hydraulic jack, the combination of: a base; a piston cylinder provided upon said base; a piston slidably disposed in said cylinder; means for forming a' reservoir upon said jack, there being formed in said base a cavity, an intake passage communicating between said cavity and said reservoir, and an exhaust passage communicating between said cavity and said cylinder'; a check valve unit disposed within said cavity; a pump barrel threadedly received into said cavity so as to hold said unit in said cavity and communicate through said unit with said inlet and exhaust passages; and a plunger slidabl disposed in said barrel.

11. n a hydraulic jack, the combination of: a base; a piston cylinder provided upon said base; a piston slidably disposed in said cylinder; means for forming a reservoir upon said ack, there being formed in said base a. cavity, an intake passage communicating between said cavity and said reservoir, and an exhaust, passage communicating between said cavity and said cylinder; a check valve unit disposed Within said cavity, said check valve unit having valved ducts therein which communicate with said intake and exhaust passages; a pump barrel threadedly received into said cavity so as to hold said unit in said cavity and communicate through said valved ducts with said intake and eX- haust passages; and a plunger slidably disposed in said barrel.

In testimony whereof, I have hereunto set 15th day of December 1924.

JOI-IN G. DYBENS.

lmy hand, at Los Angeles, California, this 

